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Development of 1D Model of Impact Force in Powertrain Equipment

Denso-Yuma Yoshimaru, Makoto Kondo, Yukie Omuro, Masashi Inaba
Published 2019-06-05 by SAE International in United States
Electromagnetic valves excellent in sealing properties and resistant to sliding are often used in powertrain equipment installed in gasoline- or diesel-engine vehicles. An electromagnetic valve has the function of moving internal valve members by means of electromagnetic force generated by the application of a voltage and thereby changing the flow path. When an electromagnetic valve operates, however, the valve members impact with one another, emitting impact noise caused by it. With the requirement for low noise in electromagnetic valves having become stricter recently from the viewpoint of comfort in the passenger compartment, predicting the noise is needed at the design stage.With this background, this paper describes the development of a 1D model of impact force that will enable the noise and the product performance to be examined simultaneously for a GDI (gasoline direct injection) high pressure pump. In contrast to the conventional model in which a movable member is taken as a mass point with a spring and a damper placed at the impact section, this paper proposes a technique in which a spring-mass model…
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Cryogenic Cam Butterfly Valve

  • Magazine Article
  • TBMG-34596
Published 2019-06-01 by Tech Briefs Media Group in United States

Typical butterfly valves cannot seal at both ambient and cryogenic temperatures. At cryogenic temperatures, valves grow and shrink, changing critical dimensions such as distance between the disc and seat. Ideally, valves would compensate. The inability of existing butterfly valves to do this led to the design of the Cryogenic Cam Butterfly Valve (CCBV) in which the disc rides on a cam shaft and is held rigid by a torsion spring that provides both axial movement of the disc in addition to the standard 90-degree rotation of a standard butterfly valve. Because the valve’s disc can rotate and translate, it can hold a tighter seal, preventing leakage despite dimensional changes caused by changing operating temperatures.

 
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Calculating the Estimated Fatigue Life of a Disc Spring

  • Magazine Article
  • TBMG-34573
Published 2019-06-01 by Tech Briefs Media Group in United States

In discussing fatigue life, it is important to distinguish between disc springs and conical spring washers, as they differ by design and intended usage. Conical spring washers are designed to provide a static thrust load in bolted joints and should not be used in fatigue applications; they are specified by DIN 6796.

 

Constructing a Concept Vehicle Structure Optimized for Crashworthiness

Dassault Systemes Simulia Corp.-Yangwook Choi, Shawn Freeman, Fabien Letailleur
Published 2019-04-02 by SAE International in United States
Multi-disciplinary optimization (MDO) of a vehicle structure at the earliest stages of design is critical as OEMs are pressed to reduce the design time in order to respond to various demands from the market. MDO for the three essential areas of performance of the vehicle structure (NVH, Crash, and Durability) needs the throughput for each of the major disciplines to be approximately in the same range of turn-around time. However, crashworthiness simulation typically takes significantly longer than the others, making it difficult to include crashworthiness in the MDO. There have been many approaches to address crash simulation in a shorter time. The lumped mass-spring method is one of the approaches but has not been widely accepted since there are many difficulties in modeling and replicating the existing structure. It required physical or Finite Element tests for all structural components to get the spring properties, and then it is hard to convert the optimized spring properties into the real design of the structural components. In this paper, a reversed workflow is presented to construct the structure…
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A New Analytical Model for Clutch System Modeling and Design Optimization

Maruti Suzuki India Ltd.-Rahul Shandilya, Vikas Rawla
  • Technical Paper
  • 2019-01-0840
Published 2019-04-02 by SAE International in United States
In manual transmission vehicles, Clutch has direct interaction with the driver and plays a significant role in defining the drivability and NVH of a vehicle. These key performance factors depend on the interaction of diaphragm and cushion springs of a clutch. For an automobile manufacturer, it’s essential to optimize the characteristics of these springs based vehicle performance requirements. A state of the art analytical model has been developed by modeling the diaphragm and cushion spring with exponential equations. Based on these models, response functions for release load, torque build-up, and pressure plate lift have been derived. Results achieved from these response functions are correlated with test data. Key contributing factors for peak clutch pedal load, vehicle launch acceleration, and disengagement point have been identified by sensitivity analysis. Multi-objective optimization is performed to select optimized parameters for vehicle performance improvement
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Composite Components for Vehicle Lightweight: Springs, Wishbones, Low-Cost Hydrogen Tanks, Demise of Astronautic Composite Overwrapped Pressure Vessel

Sardou Societe Anonyme-Max Sardou
Published 2019-04-02 by SAE International in United States
SARDOU SAS has invented in 1992 composite “C” springs (patented in 1993), these springs where offering a high energy density of 1350 joules per kilogram (compared to 300 for steel springs). This huge energy density means a potential 78% weight savings! But in the last century, weight saving was less important and platform managers were reluctant to use anything other than coil springs. So, in 2002, in order to comply with their wishes, SARDOU SAS invented composite coils springs. Easy to fit in standard suspensions, Composite coils springs are the optimum choice for McPherson-strut suspensions. As weight saving is now mandatory, composite springs, are the best choice for automotive suspensions, offering a 50% weight saving compared to steel. A Joint Venture, between SARDOU and SOGEFI Suspensions SA called S.ARA, was created in 2008 in order to mass produce composite coils springs; the official Start Of Production happen in 2014 for AUDI. This SOP has demonstrated the viability of producing composite springs. This paper describes the benefits of composite springs including the so called ‘C’ springs,…
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Quantification of Windage and Vibrational Losses in Flexure Springs of a One kW Two-Stroke Free Piston Linear Engine Alternator

West Virginia University-Nima Zamani Meymian, Nigel Clark, Jayaram Subramanian, Gregory Heiskell, Derek Johnson, Fereshteh Mahmudzadeh, Mahdi Darzi, Terence Musho, Parviz Famouri
Published 2019-04-02 by SAE International in United States
Methods to quantify the energy losses within linear motion devices that included flexural springs as the main suspension component were investigated. The methods were applied to a two-stroke free-piston linear engine alternator (LEA) as a case study that incorporated flexure springs to add stiffness to the mass-spring system. Use of flexure springs is an enabling mechanism for improving the efficiency and lifespan in linear applications e.g. linear engines and generators, cryocoolers, and linear Stirling engines. The energy loss due to vibrations and windage effects of flexure springs in a free piston LEA was investigated to quantify possible energy losses. A transient finite element solver was used to determine the effects of higher modes of vibration frequencies of the flexure arms at an operational frequency of 65 Hz. Also, a computational fluid dynamics (CFD) solver was used to determine the effects of drag force on the moving surfaces of flexures at high frequencies. A parametric study was performed to understand the effects of geometrical and operational parameters including the diameter of flexures, gap width between flexure…
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Modelling and Simulation of a Magnetorheological Fluid Damper with Multi-Accumulator during Mode Shifting

Tsinghua University-Cenbo Xiong, Liangyao Yu, Zhenchuan Li, Sheng Zheng
Published 2019-04-02 by SAE International in United States
In a monotube magnetorheological fluid damper (MRFD), there usually exists a compensation chamber with designated initial gas pressure. This enclosed compensation chamber works as an air spring to some degree to provide force to the working piston. In this work, in order to extend the external damping force range and improve the controlling efficiency, a structure of MRFD with three additional accumulators is proposed. These additional accumulators are connected to the atmosphere through an air pump and the compensation chamber with a barometric valve. The external damping force range thus can be rapidly adjusted through mode shifting with this configuration. A mathematical model of this damper with coupled effects between the air and the magnetorheological fluid (MRF) is developed. Comparing the bench tests results with some simulation outcomes, the simulation model of this MRFD is validated. Influences of moving speed of the working piston, air pressure and initial volume of the accumulators on the external performances are simulated. Simulation results tell that the coupled effects between the additional accumulators and the MRF can provide rapid…
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A Novel Dual Nonlinear Observer for Vehicle System Roll Behavior with Lateral and Vertical Coupling

Beijing Institute of Spacecraft Environment Engineering-Dong Li, Gongbo Ma
Beijing Institute of Technology-Yechen Qin
Published 2019-04-02 by SAE International in United States
The study of vehicle coupling state estimation accuracy especially in observer-based vehicle chassis control for improving road handling and ride comfort is a challenging task for vehicle industry under various driving conditions. Due to a large amount of life safety arising from vehicle roll behavior, how to precisely acquire vehicle roll state and rapidly provide for the vehicle control system are of great concern. Simultaneously, uncertainty is unavoidable for various aspects of a vehicle system, e.g., varying sprung mass, moment of inertia and position of the center of gravity. To deal with the above issues, a novel dual observer approach, which combines adaptive Unscented Kalman Filter (AUKF) and Takagi-Sugeno (T-S), is proposed in this paper. A full-car nonlinear model is first established to describe vehicle lateral and vertical coupling roll behavior under various road excitation. Considering the variation of vehicle sprung mass in the movement process, an AUKF approach is adopted to identify the sprung mass by tuning various road classification process variances of the vehicle system in real time. Then, by combing the identification…
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Inertia Tensor and Center of Gravity Measurement for Engines and Other Automotive Components

Ohio State University-Dennis Guenther
SEA Ltd.-Dale A. Andreatta, Gary Heydinger, Scott Zagorski
Published 2019-04-02 by SAE International in United States
A machine has been developed to measure the complete inertia matrix; mass, center of gravity (CG) location, and all moments and products of inertia. Among other things these quantities are useful in studying engine vibrations, calculation of the torque roll axis, and in the placement of engine mounts. While the machine was developed primarily for engines it can be used for other objects of similar size and weight, and even smaller objects such as tires and wheels/rims.A key feature of the device is that the object, once placed on the test table, is never reoriented during the test cycle. This reduces the testing time to an hour or less, with the setup time being a few minutes to a few hours depending on the complexity of the shape of the object. Other inertia test methods can require up to five reorientations, separate CG measurement, and up to several days for a complete test.The device uses a system of pivots, springs, and three sensors to get the three moments and three products of inertia, plus the…
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